1. Field of the Invention
The present invention relates to a machine including a mobile machine frame which is arranged on chassis units, including a working unit and adjusting drives adapted to adjust the working unit relative to the machine frame for establishing a design track position, and including a measuring unit of an absolute measuring system having a laser emitter adapted to register fixed points which have been geodetically surveyed and which define the absolute track position.
2. Description of the Prior Art
A measuring platform with a laser emitter which is coupled on in front of a maintenance machine and travels on tracks is already known by the international patent application WO 93/06303. A space stabilized gyro-platform, which is also arranged on the measuring platform registers the absolute change of position of the measuring platform, serves for a correcting of the angle change values of the laser emitter. The extent of the traveled path is measured either with a separate measuring device measuring the traveled distance or by means of the gyro-platform. The actual position relative to fixed points determined from these data is compared with the design value according to the survey map and if necessary a correcting of the track is performed based on this value.
The CH 684 026 A5 describes a method of measuring relative angles between a reference direction of a measuring platform and fixed points located at a distance therefrom by means of light rays originating at the measuring platform. They are reflected back by reflecting means placed at the fixed points and are received and processed by receiving means foreseen at the measuring platform.
In a technical article with the title "Automatische Steuerung von Gleisbaumaschinen nach Vermessungsfixpunkten" (Automatic controlling of track construction machines in accordance with survey fixed points) of the periodical "Der Eisenbahningenieur", September 1990, pages 459-462 a laser control is described which operates with absolute measuring bases for the leveling and aligning by a track packing machine. This laser control consists of a rotatable laser emitter emitting a fan-shaped beam which is controlled from the track packing machine by wireless, a measuring car with a laser receiver for the leveling and aligning and a computer for the calculating of the position of the track.
Finally, a measuring vehicle with an inertial navigation system for recognizing errors of track positions is known according to an article "Lasertechnik und INS" by the periodical "Der Eisenbahningenieur"; August 1995, pages 552-558.